/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile.editor;

import proguard.classfile.*;
import proguard.classfile.attribute.CodeAttribute;
import proguard.classfile.instruction.*;
import proguard.classfile.instruction.visitor.InstructionVisitor;
import proguard.classfile.util.SimplifiedVisitor;

/**
 * This InstructionVisitor adds all instructions that it visits to the given target code attribute.
 *
 * @author Eric Lafortune
 */
public class InstructionAdder extends SimplifiedVisitor implements InstructionVisitor {
    private final ConstantAdder constantAdder;
    private final CodeAttributeComposer codeAttributeComposer;

    /**
     * Creates a new InstructionAdder that will copy classes into the given target code attribute.
     */
    public InstructionAdder(ProgramClass targetClass, CodeAttributeComposer targetComposer) {
        constantAdder = new ConstantAdder(targetClass);
        codeAttributeComposer = targetComposer;
    }

    // Implementations for InstructionVisitor.

    public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset,
        Instruction instruction) {
        // Add the instruction.
        codeAttributeComposer.appendInstruction(offset, instruction);
    }

    public void visitConstantInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset,
        ConstantInstruction constantInstruction) {
        // Create a copy of the instruction.
        Instruction newConstantInstruction = new ConstantInstruction(constantInstruction.opcode,
            constantAdder.addConstant(clazz, constantInstruction.constantIndex), constantInstruction.constant);

        // Add the instruction.
        codeAttributeComposer.appendInstruction(offset, newConstantInstruction);
    }
}